Abstract: With the problem of normal JONSWAP spectrum unsuitable for offshore wave simulation, an improved JONSWAP spectrum is proposed, which added a depth factor based on study of the relationship between waveform parameters and water depth. Through analyzing the traditional wave fractal algorithm, it is found that large span of information transfer between adjacent interpolation points is the key reason of wave creases and spikes phenomenon. Therefore, a new threshold peak filtering algorithm using square -square fractal is proposed. The results of simulation experiment with OpenGL show that the improved JONSWAP spectrum is suitable for offshore wave simulation, which can generate realistic, smooth, soft shallow waves. The new fractal algorithm can effectively reduce the wave creases and spikes phenomenon. It has a good sense of reality and real-time, and can reach the purpose of shallow offshore simulation in real-time.

Key words: offshore simulation, improved JONSWAP spectrum, square-square segment method, threshold peak filtering algorithm

摘要： 针对经典JONSWAP谱不适合模拟浅水海浪的问题，在研究水深与波形参数关系的基础上，提出了一种加入深度因子的改进JONSWAP谱。通过分析传统海浪分形算法，得出相邻插值点之间信息传递跨度过大是产生波浪折痕、尖峰现象的主要原因。为此提出了一种新的方形-方形细分阈值滤尖峰算法。OpenGL仿真结果表明，改进的JONSWAP谱适合于模拟近海，可以生成的逼真、平滑、柔和的浅水海浪。新的分形算法能有效地减少生成波浪的折痕、尖峰现象，具有较好的真实感和实时性，达到了近海浅水实时仿真的目的。

关键词: 近海模拟, 改进JONSWAP谱, 方形-方形细分法, 阈值滤尖峰算法